Flour product and method of making



Aug- 13, 1968 E. L. GALLE 3,397,067

FLOUR PRODUCT AND METHOD OF MAKING Filed Jan. 20, 1967 4 Sheets-Sheet lINVENTOR. Eon/Aap 64.445

C Z'OPIVE V Aug- 13, 1968 E. L. GALLE 3,397,067

' FLOUR PRODUCT `AND METHOD OF MAKING 4 Sheets-Sheet 2 Filed Jan, 20,1967 .lllmlmilih HIM.,

INVENTOR. bu/412D A. GALLE Arf-02415;

ug- 13, 1968 5.1.. GALLE l 3,397,067 v FLOUR PRODUCT AND METHOD OFMAKING Filed Jan. 20, 1967 4 Sheets-Sheet 3 Fl TER S IF TEE FIE 8INVENTOR. lo/44420 L. 6,4

Aug. 13, 1968 E. 1 GALLE 3,397,067

FLOUR PRODUCT AND METHOD OF MAKING Filed Jan. 20, 1967 4 Sheets-Sheet 4INVENTOR.

EDM/@ .4. 64u45' United States Patent O 3,397,067 FLOUR PRODUCT ANDMETHOD OF MAKING Edward L. Galle, St. Paul, Minn., assgnor to ThePillsbury Company, Minneapolis, Minn., a corporation of DelawareContinuation-in-part of application Ser. No. 382,283,

July 13, 1964. This application Jan. 20, 1967, Ser.

10 Claims. (Cl. 99-93) ABSTRACT OF THE DISCLOSURE Agglomerating highprotein ne cereal liour by increasing the moisture content, briey mixingand agitating the moistened flour in a first zone, immediatelytransferring the flour to at least one other mixing zone, continuing themixing and agitation until sufficient bonding has occurred, then dryingthe agglomerates.

This is a continuation-in-part application of my prior applicationUnited States Serial No. 382,283, filed n July `13, 1964, now abandoned.

This invention relates to novel methods and apparatus for agglomeratingcereal iiour particles to improve the physical characteristics thereofand the resulting novel agglomerated product, and more particularly tothe agglomeration of a high protein ne particles size flour fractionwhich is particularly well suited for blending purposes to make premiumbakery iiour.

Flour in general and the aforementioned high protein fine fraction iiourin particular has always been exceedingly difficult to handle inconventional flour processing and handling systems. The fine fractionflour particles exhibit very poor iiow characteristics, being even moredifficult to handle than most conventional types of flour, and incapableof being sifted by conventional sifting means.

The high protein fine flour fraction under consideration is normallyderived by the air separation or fractionation of milled cereal iioursincluding soft and hard wheat, rye, barley, corn, durum and rice andconsists of exceedingly iine particles most of which are less than 20microns in size, the average size thereof normally being in the range of3 to 5 microns. This fraction consists principally of protein and starchwith a small percentage of fat present.

Because of the poor ow characteristics of high protein fine fractionliour, its difculty in handling and its non-adaptability to conventionalour processing and handling systems, its use has been seriously limitedand curtailed despite the fact that it has a number of very desirableuses and applications such as a bread our additive or improver, thishigh protein fine fraction p-roduct imparting improved grain and textureto the bread product formed therefrom. The poor owability of this finefraction is due not only to the very tine particle size but also to 'theelectrostatic charge carried by said particles.

The primary purpose of this invention is to provide an improved iiourproduct and particularly an improved high protein ne fraction product,which overcomes the aforementioned problems and which more particularlyis free-flowing, dust-free, and easily handled and capable of being usedin conventional our processing and handling systems so as to extend theuse thereof.

Another object of this invention is to provide a method and apparatusfor forming the aforementioned improved product.

Another object of the invention is to provide an improved method andapparatus for forming agglomerated high protein compositionscharacterized by producing uniform agglomerates at relatively high flowrates without the tendency for the apparatus to become plugged with3,397,067 Patented Aug. 13, 1968 rice undesired accumulations ordeposits of moist material.

A further object of the invention is to provide an improved method andapparatus of the type described wherein agglomerates are subjected tomixing in two successive mixing zones including a iirst zone forproviding uniform and thorough mixing and a second zone for mixing thepreviously moistened material for a relatively long period of time.

A further object of the invention is the provision of an improvedagglomerating method and apparatus for pulverulent material having ahigh protein content wherein the moistened material is first subjectedto turbulent and vigorous mixing and is then immediately suspended in astream of heated drying gas.

Still another object is to provide an improved flour product andparticularly an improved high protein fine yfraction product whichexhibits improved baking characteristics as compared with the samematerial in its conventional form. The following disclosure is directedparticularly to high protein line fraction flour and methods andapparatus for treating same. However, the invention is not necessarilylimited thereto, the methods and apparatus disclosed hereinafter alsobeing applicable to other forms of our. p

These and other objects and advantages of this invention will more fullyappear from the following description made in connection with theaccompanying drawings, wherein like reference characters refer to thesame or similar parts throughout the several views, and in which:

FIGURE 1 is a ow diagram of a continuous process Ifor carrying out thisinvention.

FIGURE 2 is a side elevational view (with portions broken away) of theagglomerator of FIGURE 1.

FIGURE 3 is an end elevational view of the agglomerator of FIGURE 2 asviewed from the left side thereof.

FIGURE 4 is an enlarged detail view of the liquid feed assembly used inthe agglomerator of FIGURE 2.

FIGURE 5 is an enlarged detail sectional view of the seal between themoisturizing ycylinder and the feed hopper.

FIGURE 6 is an end elevational view of the agglomerator of FIGURE 2 asviewed -from the right side thereof.

FIGURE 7 is an end elevational view of the right end of the apparatus asseen in FIGURE 4.

FIGURE 8 is a semi-diagrammatic illustration of another form ofapparatus in accordance with the invention.

FIGURE 9 is a partial end elevational view of the twostage mixer inaccordance with a modified form of the invention.

FIGURE l0 is a sectional view taken on line 9 9 of FIGURE 8.

For convenience, the high protein fine flour fraction underconsideration is hereinafter referred to as HPFF. For purposes of theapplication, high protein fine fraction flour (HPFF) contains 18-23%protein and has a maximum Fisher particle size value of 5.0.

I have found that the aforementioned problems can be overcome and HPFFplaced in an improved form capable of being readily handled inconventional material handling systems by assembling the fine particlesthereof into porous agglomerates. These agglomerates consist of aplurality of fine particles of HPFF randomly clustered together andbonded at their interfaces by protein. These particles define amultiplicity of interstices and voids therebetween which provide theagglomerates with the aforementioned porous structure and provide aliquid access to the agglomerate interior so as to facilitate thewetting of he particles forming the agglomerate and the 3 dispersionthereof in a liquid. HPFF in this agglomerated form is free-flowing,dust-free and easily handled in conventional our processing and handlingsystems. The agglomerated HPFF h-as a higher bulk density than thenonagglomerated HPFF and therefore occupies less space, therebysimplifying and reducing the cost of storing and packaging same. Thishigher bulk density is somewhat surprising in view of the fact that mostknown agglomerated produc-ts have a lower bulk density than the startingmaterial. The agglomerates also exhibit improved baking characteristicsas compared with the non-agglomerated material.

The method or process of this invention for -agglomer- `ating HPFF canbe carried out on a lbatch or continuous basis, the continuous processbeing more practical and commercially attractive. Preferred embodimentsof the invention are illustrated -in the accompanying drawings anddescription.

The process for agglomerating HPFF broadly comprises moisturizing theparticles with sucient moisture to form adhesive surfaces thereoncombined with agitation of a mass of these moistened adhesive particleswhereby they are brought into random contact with each other and therebyform the desired agglomerates.

In order to obtain the most desirable type of agglomerate and to achievemaximum efficiency in the agglomeration, the amount of moisture added tothe material to be agglomerated -is preferably carefully controlled soas to provide enough moisture to achieve the degree of adhesiveness onthe particles suicient to form a strong bond between the particlescomprising the agglomerates, and also to prevent over-moisturization andthe resultant excessive glutenization of the protein which is normallyconsidered undesirable. Investigation and experimentation has indicatedthat agglomeration can be accomplished by increasing the moisturecontent of the material to a total moisture content of about -35% duringagglomeration. When the total moisture is 22% or lower, the agglomeratesare quite soft and fragile and therefore are generally consideredunsuitable for bulk handling because of their tendency to break downhandling. Total moisture contents of andhigher generally represent someexcessive moisture not needed for successful agglomeration which maycause Some excessive gluteniza-tion of the protein and put a greater(and normally unnecessary) load on the drying equipment used to removethe added moisture from the agglomerates after the formation thereof.The optimum moisture content for agglomeration is dependent on the formof the invention as will be illustrated below.

To assemble the moistened particles into the desired agglomerates, it ispreferable to repeatedly agitate (as by shaking) a mass of materialafter the initial moisturization thereof for a period of time which issufficient to enable the moisture added to `the material to be absorbedby and react with the particles to form the degree of adhesivenessdesired and required to effect the agglomeration. The moistenedparticles are also maintained in dense, intimate relationship with eachother during this agitation whereby they make repeated random contactwith each other so that when they develop the necessary degree ofadhesiveness they stick together in clusters and form porousagglomerates.

In one preferred form of this invention, the material to be agglomeratedis fed to a chamber where it is dispersed and has the desired amount ofmoisture added thereto while in the dispersed condition, the moistenedmaterial thereafter being discharged from said chamber and moved enmasse in supported fashion along a predetermined path of travel whilebeing simultaneously and continuously agitated with the desiredagglomerates having been formed by the time the material reaches the endof said predetermined path of travel. Alternatively, the moisturizedmaterial may be permitted to remain in the moisturizing chamber withsuitable agitation provided therefor in said chamber for the period oftime necessary to complete the agglomeration, the addition of moistureto said chamber being stopped as soon as the predetermined amountnecessary to achieve the agglomeration has been added, with theagitation continuing lthereafter.

In another form of the invention, the flour is moistened and subjectedto vigorous mixing in la highly turbulent state in two successive mixingzones, the first zone being characterized by providing extremely highturbulence and thorough mixing during a relatively brief treatmentperiod and the second treatment zone being characterized by providingcontinued mixing of the preinoistened material over a substantiallylonger period of time. The agglomerates produced in the second mixer arethen immediately introduced to a rising stream of a heated drying gas.

After formation of the agglomerates, they are preferably dried,preferably immediately and preferably to a total moisture content of notmore than 14%.

The temperature of the agglomerating system normally should becontrolled and maintained at a suliciently low temperature so that noundesirable changes occur in the physical and chemical make-up of thematerial, such as gelatinization of the starch or degradation of theprotein.

In a continuous process, it is also import-ant that the HPFF in thefeed-in system which delivers the material to the agglomerator be keptcontinuously moving in said feed-in system during the agglomerationoperation. If the feed is interrupted and the movement of the materialin the feed-in system momentarily stops, the poor flow characteristicsof the unagglomerated material make it difficult to get theunagglomerated material moving again in the feed-in system.

After the agglomerates have been formed and dried, they may be usedeither in said dried form or may be reu duced in size if desired such asby grinding, the ground agglomerates retaining their agglomerated formand freeflowing characteristics, the reduction in size as by grindingreducing only the size of the agglomerates and not the characterthereof.

FIGURE l is a flow diagram of one complete preferred continuousagglomeration process for carrying out the agglomeration of HPFF andother our material. As can be seen in said flow diagram, theunagglomerated pulverant material is first passed through a sifter S,from Wence the sifted material is continuously conveyed and elevated bya lift L to a metering mechanism M which continuously discharges thematerial to be agglomerated at a predetermined uniform rate to the inputside of an agglomerator A. The material passes through the agglomeratorA and is discharged therefrom in the form of porous agglomerates, theagglomerated material passing directly from the agglomerator to a dryerD. The dryer may be of any suitable type, one preferred type being oneutilizing a vibrating screen in which the wet agglomerates pass acrossthe screen and are agitated in the course of said travel by thevibration of said screen, the agglomerates being dried as they passthereover by means of warm air entering through the bottom of the dryerand passed upwardly through the screen and the agglomerates thereon, theair being removed continuously from the top of the dryer and sent to aseparator C where any entrained material is extracted therefrom. Thedrying air is supplied by a fan F which propels the air through a heaterH and thence onto the dryer. The dried agglomerated product issuing fromthe dryer may be used as such, or it may be sent to size reductionmechanism such as the conventional two-high roll mill R illustrated forreducing the size of the agglomerates. The auxiliary equipment (otherthan the agglomerator A) such as the aforementioned sifter S, lift L,meter M, dryer D, roll mill R, fan F and heater H may be of any suitabledesign and construction capable of carrying ont their intended purpose,and do not constitute a part of this invention per se, and a detaileddescription thereof is not believed necessary for a full and completeunderstanding of this invention.

The illustrated agglomerator A, which is one preferred apparatus forcarrying out the method and forming the agglomerated product of thisinvention includes a main supporting base having a pair of upstandingtransversely spaced apart supporting members 11 mounted thereon adjacentthe input end of the agglomerator. These members 11 support a feedhopper 12 mounted thereon, which hopper includes a vertical feed tube13, through which the material enters the agglomerator, an ellipticalangularly oriented access hopper tube 14 having a cover 14a hingedthereto, and a generally horizontally oriented cylindrical dischargemouth 15 in communication with said tubes. An air operated vibrator 16is provided for vibrating the feed hopper to prevent plugging thereofand insure a constant flow of material therethrough, said vibrator beingsuspended from and supported by said feed hopper by means 0f a mountingbracket assembly 16a.

An eccentrically rotatable cylindrical moisturizing chamber 17 isprovided which is rotatably journaled on the cylindrical discharge mouth15 of the feed hopper for rotation relative thereto about axis X, saidmoisturing chamber being eccentrically mounted with respect to axis Xfor a purpose hereinafter to be described. The side wall 17a of themoisturing cylinder 17 adjacent the feed hopper has a circular openingformed therein for receiving material from the hopper, said openingtelescopically receiving the discharge mouth 15 of the hopper and beingconcentric therewith and with the rotation axis X, material entering themoisturizing chamber from the hopper by gravity flow.

To seal the joint between the hopper and the moisturizing cylinder, aseal assembly (best seen in FIGURE 5) is provided. This assemblyincludes an annular mounting flange 18 carried by the hopper, whichflange supports an annular cup-shaped seal retainer 19 by means of alongitudinally adjustable mounting bolt 20. An annular resilient sealingring 21 is provided which is held against the outer face of the sidewall 17a in sealing engagement therewith by means of the retainer 19.

An agglomerating section is provided for conveying the wetted particlesalong a predetermined path of travel and agitating and bringing thewetted particles into repeated random contact with each other duringsaid travel to form the desired agglomerates.

The agglomerating section comprises a series of cylindrical tubularsections or legs 22', 22 and 22 (seven are illustrated) of the samecross sectional size which are joined together in end-to-endrelationship in flow cornmunication with each other, with adjacent legsbeing angularly offset from each other as illustrated to provide azig-zag arrangement, with alternate legs being in parallel relationshipto each other. Thus, the first, third and fifth and seventh legs of theseries are parallel to each other, as are the second, fourth and sixth.The entire section is rotatable about the rotation axis X, with each leghaving the same relationship to said rotation axis, with thelongitudinal axis of each leg being in diagonal intersectingrelationship to said rotation axis.

The first leg 22 of the series is joined to the side wall 17b of themoisturizing cylinder for simultaneous rotation of said cylinder andagglomerating section, a discharge opening being provided in said sidewall 17b in communication with the first leg 22 for discharging wetparticles from cylinder 17 into leg 22', the discharge and inletopenings in the moisturizing cylinder being in generally opposedrelationship.

Because of the eccentric mounting of the moisturizing cylinder 17, itraises and lowers its charge once each revolution. When it is raisingthe charge, the adjacent first leg 22 of the zig-zag section isdescending and material flows from that leg from the moisturizingchamber until said leg is filled. When the moisturizing cylinder isswinging downwardly so as to lower its charge, some but not all of thematerial in the first leg falls back again into the moisturizingchamber.

To moisturize the material in moisturizing cylinder 17, a novel liquidfeed assembly indicated in the entirety by 23 and best seen in FIGURES 4and 7 is provided. Said assembly includes a dispersion head 24 which ismounted on the inner end of a hollow drive shaft 25 and rotatably driventhereby inside the cylinder 17. The drive shaft 25 extends through andis supported by a bracket 26 forming a part of the hopper structure 12,and also extends through the back wall 14b of the access tube 14 intothe cylinder 17.

The drive shaft is enclosed by and rotatably journaled on bearings 27and 28 within an annular housing 29 which is secured to bracket 26 byany suitable means, such as welding.

The bore 25a of the drive shaft serves as the means for conveying liquidto the dispersion head, the liquid being supplied to the bore of thedrive shaft through a rotating union 30 connected with the outer end ofthe drive shaft.

The drive shaft is driven by a motor 31 mounted on the base 10, saidshaft and motor being drivingly interconnected by means of pulleys 32and 33 drivingly connected to said shaft and motor respectively, and anendless drive belt 34 trained about said pulleys and enclosed by aprotective belt guard 35.

The dispersion head 24 comprises a sleeve 36 telescopically mounted onthe inner end of shaft 25, said sleeve having mounting flanges 36a and36b formed on opposite ends thereof, and openings 36C formed thereinaligned with similar openings 25b in the drive shaft for admittingliquid into the interior of the dispersion head from the bore of thedrive shaft. Three oblique cylindrical sections 37, 38 and 39 aremounted on sleeve 36 to form a hollow drum which defines an annularchamber 40 from which the liquid is dispensed to the material to beagglomerated. The end wall of the inner end section 37 has an axialopening 37a for receiving the drive shaft. End sections 37 and 39 aresecured to their respective flanges 36a and 36b by fasteners 41, andcenter section 38 is fastened to sleeve 36 by four radial braces 42extending therebetween and connected thereto. The center section has apair of parallel oblique rims which are opposed by and slightly spaced(a few thousandths of an inch) from the complementary oblique rims ofthe end sections 37 and 39, the opposed spaced apart oblique rimsdefining annular obliquely oriented orifices 43 and -43 lwhich becomewhirling orifices when the dispersion head is rotated.

A metered flow of agglomerating liquid passes through bore 25a -of thedrive shaft, enters the annular chamber 40 through the aligned openings25b and 36C, is subjected to centrifugal pull through the whirlingorifices and is broken up and subdivided thereby and is thrown radiallyoutwardly therefrom as a fog of very small finely atomized liquidparticles against the material lining the inner wall of the cylinder 17.The orifices 43-43 are disposed at an angle so that the fog emerges as awide band rather than in a narrow pattern or stream. This achieves moreuniform distribution of the liquid and wetting -of the fine pulverulentparticles to be agglomerated.

To aid in dispersing the particulate material in cylinder 17, thedispersion head is provided with a plurality of L-shaped dispersionblades 44 and C-shaped dispersion blades 45 which are mounted on theirrespective head sections by fasteners 46 so as to extend radiallytherefrom. These blades are uniformly spaced about the entirecircumference of the head and uniformly spaced axially thereof.

As the particulate material is fed into cylinder 17, it is dispersed bythe whirling action of the dispersion head 24 and its blades and thrownoutwardly against the wall of cylinder 17 to form a continuous layer ofmaterial thereon. The material is preferably fed to the cylinder 17 atsuch a rate that the cylinder wall is completely lined with materialduring rotation thereof to prevent the liquid from directly wetting saidwall and achieve Amore uniform wetting of the particulate material.

The zig zag portion of the agglomerator is provided with means forsupporting and rotating same. Said means includes a circular drive tire47 and circular idling tire 48, said tires encircling the zig zagportions and drivingly connected to the tubes 22 enclosed thereby, saidtires being coaxial with respect to axis X.

Each of said ytires is supported for rotation on a pair of rollers 49,which rollers are supported by upstanding bifurcated brackets 50 whichin turn are mounted on respective supporting blocks 51 and 51 which restato-p the base 10.

Guide wheels 52 rotatable about a vertical axis are provided on oppositesides of the idling tire in engagement therewith to prevent axialshifting movement of the idling tire and zig zag section during use. Theguide wheels are supported by brackets 53 mounted on block 51.

To rotate the agglomerator about axis X, an annular drive sprocket 54 isprovided which circumscribes the zig zag section and is drivingly andcoaxially connected to the drive tire by members 55. A motor 56 ismounted on the base 10, said motor having a drive sprocket 57 mounted onthe motor shaft, which sprocket is drivingly connected to the otherdrive tire sprocket 54 by means of an endless drive chain S8. An annularchain guard 59 is also provided which is mounted on block 51' and whichencloses the drive tire sprocket and the drive chain.

A discharge chute 60 is mounted on the base 10 by means of a supportingmember 61, said chute completely enclosing the open discharge end of thedischarge tube 22" which rotates freely within and relative to saidchute.

The back of the chute is closed by an annular seal ring w plate 62aflixed to a seal ring collar 63 carried by tube 2". A pair of sealingrings 64 are secured to the plate 62 adjacent the outer edge theerof onopposite sides thereof and are maintained in sealing engagement with thechute by means of a pair of guide assemblies 65 carried by the chute.

In operation, the unagglomerated HPFF is continuously fed to the hopper12, from whence it continuously passes directly into the moisturizingcylinder 17. A metered flow of liquid (such as water) is simultaneouslyfed to the dispersion head 24 through the drive shaft 25, said headcentrifugally throwing and spraying fine droplets offwatercircumferentially thereof towards the peripheral wall of themoisturizing cylinder and about the entire circumference thereof.

Because the material coats or covers the inner wall of the moisturizingcylinder, no water reaches or makes contact with the wall of the chamberand thereby prevents fouling of said chamber and a build-up of stickymaterial thereon. As a result of the eccentric rotation of themoisturizing chamber, a continually renewing array of differentparticles are presented to the liquid fog. Thus, the solid and liquidconstituents are uniformly blended together so that the liquid isuniformly distributed among and on the fine flour particles.

The material fed into the moisturizing cylinder gradually works its wayfrom the feed side to the discharge side of said cylinder, and a setamount is then discharged therefrom into the first of the zig zagsections 22', and then gradually progresses longitudinally of the zigzag portion through successive tubes 22 until it ultimately emerges fromthe discharge tube 22" in agglomerated form, the agglomerates issuingfrom tube 22" being dumped into chute 60 from which they pass to thedryer D through discharge mouth 60a of said chute.

When the apex V of the joint between any two adjacent zig zag tubes ispointed upwardly, the material in said adjacent sections tends to fallaway from said apex. When said apex is pointed downwardly, the materialin said adjacent sections tends to move towards said apex. The

movement of said apex from a downwardly pointing to an upwardly pointingposition causes a portion of the material located in the area aroundsaid apex to move downstream towards the next V apex to progressivelymove the material through the zig zag section towards the discharge tube22 for ultimate discharge thereform. Thus, in progressing through therotating agglomerator, the material is constantly recycled forward andbackward at each V-junction during each revolution. With eachrevolution, a uniform quantity of material is discharged from the lastleg 22".

This repeated longitudinal reciprocating movement of the particles ineach of the zig zag sections combined with the general radial or lateralmovement therewithin occasioned by the continuous rotation, causesrepeated agitation and shaking and thorough intermixing and repeatedcontact of the wetted particles which achieves the agglomerationdesired. Thus, the wetted particles are subjected to a gentle tumblingaction and rolling type movement over each other in which all of theparticle movement including movement longitudinally of the tubes iseffected by gravity forces. The individual particles and theagglomerates formed therefrom are not crushed, smeared or subjected toexcessive mechanical working. Recycling of wet material takes placecontinuously with backward and forward traverses occurring at random,whereby virtually all of the wet particles are assured of beingassembled into agglomerates before being discharged from theagglomerator, and thereby assuring a higher percentage yield ofagglomerated product. The particles are shifted upstream and downstream,with the net flow being downstream, with the overall situation being oneof flow equilibrlum. At each leg, back and forth How conditions arestabilized.

The discharge leg 22 dumps its charge each revolution, and is the onlyleg of the zig-zag that handles a unidirectional ow. Every leg upstreamtherefrom has a downstream flow for a half revolution followed 'by anupstream ow during the other half revolution. The differences betweenupstream and downstream flows in all legs are equal. All thesedifferences, under equilibrium conditions, equal the periodic dischargethat occurs at the last leg of each revolution.

Flows and discharges in the series of legs are all different, eventhough the flow differences are equal. The legs carry progressivelysmaller charges as the material moves downstream.

Recycling of material occurs at each apex V during each revolution. Aportion of the material held by that part goes downstream the rest goesupstream.

The multiple recycling steps afforded by this apparatus completelylevels off any feeder ow variations. There are no screens, baffles, orimpellers in the path of the wetted particles to damage said particlesor the agglomerates formed therefrom.

The inlet end of the agglomerator is slightly higher than the dischargeend thereof with the axis X being slightly downwardly inclined in thedirection of flow (from left to right as viewed in 'FIGURE 2) to assurethe continuous movement of the material through the agglomerator. Therate of flow of material through the agglomerator can be readilycontrolled by controlling the speed of rotation and the angle of tilt ofthe axis of rotation X. Thus, the time which the material spends in theagglomerator can be regulated within broad limits so as to achieve theamount of particle contact necessary for proper agglomeration. It willalso be understood that the zig-zag section is of sucient length thatthe wetted particles will be retained therewithin long enough to permitthe desired degree of adhesiveness to develop on the particles and tofurther achieve the desired degree of intermixing of the particlesnecessary to achieve the agglomeration.

The agglomerates formed by the aforedescribcd method on the apparatusdisclosed .and described are of substantially uniform size and have anaverage size of about 10 mesh, with 90% of the agglomerated Imaterialbeing between 10 and 50 mes'h. If desired, the size of the agglomeratescan be reduced `by conventional roll mill grinding, e.g. 100% less than30 mesh without destroying the desired characteristic of theagglomerated product. The agglomeration of the HPFF materially increasesthe bulk `density thereof, the 10 mesh material having a 'bulk densitywhich is between two and three times as large as that of theunagglomerated control material. Thus, for example, a typical controlsample of unagglomerated HPFF had a loose bulk volume of 6.06 ft.3/cwt.(l6.5#/ft.3) and a vibrated bulk volume of 5.0 ft.3/cwt. (20.0#/ft.3).The same material as agglomerated (l mesh) had a loose bulk volume of2.3 ft.3/cwt. (42.4#/ft.3) and a vibrated bulk volume of 2.11 ft.3/cwt.(47.4#/ft.3). The same agglomerated 4material ground to 30 mesh size hada loose vbulk volume of 2.96 ft.3/cwt. (33.8#/ft.3) and a vibrated bulkvolume of 2.59 ft.3/cwt. (38.6#/ft.3). Thus, the foregoing figuressharply illustrate the substantial decrease in bulk volume and thecorresponding increase in bulk density resulting from the agglomerati-onof HPFF. As `an illustration of the improved ilowability achieved Ibyagglomeration, unagglomerated control HPFF and agglomerated HPFF groundto 30 mesh were tested on similar equipment which included dischargefrom a vibrating discharge spout or cone. The equipment used to measurethe owability lcomprised a funnel having a coarse screen at the spoutwith steel balls on the screen to furnish the agitation, the entirefunnel being vibrated magnetically. This apparatus shows a greatsensitivity to flow rate. It took tive minutes to discharge 45 grams ofunagglomerated HPFF. In contrast, the same amount of the agglomeratedmaterial was discharged in 40 seconds. In another test, 3 samples y(10g., 30` g., 50` g.) each of the agglomerated and unagglomerated materialwere run through the test apparatus with the following results:

Baking tests utilizing unagglomerate-d and agglomerated HPFF indicatedimproved baking qualities for -the agglomerated material. Bread bakedfrom agglomerated HPFF has improved internal characteristics includingbetter grain and texture than bread baked from unagglomerated HPFF.

In a typical successful operational run, HPFF having about 20% proteinand a Fisher size of about 4.0, was agglomerated in apparatus similar tothat illustrated. The agglomerator had 7 legs in the zig-zag section,said legs being 10 inches in diameter, with the tive intermediate legsbeing 21 inches long7 the end legs 22 and 22l being proportionatelyshorter. The moisturizing cylinder was lOl/ inches long and 211/2 inchesin diameter. The axis of rotation was set at `an angle of about 2, andthe speed of rotation of the zig-zag and moisturizing cylinder was 20r.p.m. It took about -20 seconds for agglomerated material to beginbeing discharged. The material fed to the agglomerator contained 9%moisture. The water disperser was operated at 1600 r.p.m. The materialwas fed in at a rate of 25 pounds per minute, and water entered throughthe disperser at 5 pounds per minute resulting in the wet agglomerateshaving a moisture `content of 24%. The agglomerates were dried to about13% t-otal moisture. The agglomerates formed had all the aforementionedphysical characteristics and advantages.

The aforedescri'bed system can be successfully operated within thefollowing ranges:

(a) HPFF feed-in of 15-31 pounds per minute;

(b) Water additions of 3-6 pounds per minute;

(c) Water Adisperser speed of 1400-3000 rpm.;

Cil

(d) Agglomerator (blender) speed of 16-30 r.p.m.

(e) 2-21/2 degrees slope in the axis of rotation.

Thus, a desirable wetting rate is to yadd about one pound of water perminute to each -five pounds of HPFF to be agglomerated, which gives thewet agglomerates a moisture content of 23 to 25%. If the moisturecontent is too great, coarse lagglomerates or pills Awill form.

The particles comprising the HPFF agglomerates are self-bonded to eachother by the wetted protein in the material, which protein becomes tackyand adhesive when enough moisture is added thereto. The same is true ofany other type of our containing product agglomerated according to thisinvention in which the major portion of the product consists of our.Thus, the invention applies to the agglomeration of material containingonly flour, and to the agglomeration of a mixture of flour and nonourmaterial in which the our comprises the major portion of the mixture andthe moisturized protein thereof serves as the primary bonding agent inthe agglomerated product, and to any flour containing product in whichadhesive surfaces can be formed on the particles comprising same by theaddition of moisture thereto.

The Fisher values referred to herein were arrived at in |accordance withthe standardized method of conducting the Fisher Subsieve Size Test asdescribed in the publication of B. Dubrow, Analytical Chemistry, volume25, 1953, pp. 1242 to 1244; Fisher Scientific Co. (Pittsburgh, Pa.),Directions for Determination of Average Particle Diameters, etc.

Although water is a preferred liquid used to agglomerate HPFF, it willbe understood that other liquids capa- =ble of forming adhesive surfaceson the particles can be used and come within the scope of thisinvention. It will be further understood that the apparatus illustratedand described is but one preferred means for carrying out theagglomeration of the material under consideration, and that theinvention is not necessarily limited thereto, other apparatus capable ofcarrying out the method of this invention coming withing the scopehereof.

Flour material yother than HPFF can be successfully agglomerated by themethod and in the apparatus hereinbefore described, typical examplesbeing plain conventional cereal flour, high protein fine fraction flourhaving a protein content higher than that of HPFF (and which alsousually has a Fisher value not greater than 5.0), and vital wheatgluten. The later usually has about protein (with the remainder beingmostly starcih), but the protein content may vary therefrom somewhatwithin the broad range of about 70-90%. A typical specific example ofvital wheat gluten agglomerated according to this invention is asfollows: vital wheat gluten containing 78% protein and 51/2% moisturewas fed to the agglomerator at a rate of 10 pounds per minute and wasmoisturized therein by water fed to the agglomerator at a rate of 2.2pounds per minute, thereby increasing the moisture content of the glutenby 22% to a total moisture level of 22.5%.

Refer now particularly to FIGURES 8, 9 and 10 which illustrate anotherform of the invention. In accordance with this form of the invention thematerial to be agglomerated such las high protein flour `66 of the typedescribed above is introduced into a hopper 67 having a verticallyadjustable flow control gate at its lower end. The our 66 passes beneaththe gate 68 `as a bed having uniform thickness on the upper surface ofan endles belt conveyor 69 which is driven in the appropriate directionto advance the material toward the left as seen in FIGURE 8. The flourthus passes off the end of the conveyor, as seen in FIGURE 9, at auniform and controlled nate into a hopper 81 through a shut-off valve82, a duct 83 to a mixer 72 which consists of a. horizontally disposedcylindrical casing having an axially extending and horizontally disposedrotatable mixer shaft 72a to which are secured longitudinally spacedradially extending blades 72b. Each of the blade is mounted at an angleof about relative to the axis of shaft 72a. In a typical application,the mixer 72 is about 8` inches in diameter and about 30 inches long.The blades 72b are spaced about 1/16 inch from the inside surface of thecasing. Moisture in the form of either water or steam is introduced intothe casing through a line 72C and valve 72d. The moisture content of theflour is preferably brought to a level between about Ell-32% by weight.If substantially less moisture is used, the agglomerates will be soft.If the moisture content is too great, coarse agglomerates or pills willform.

Rotaiton is imparted to the shaft 72a by a suitable driving means suchas electric motor 73. The mixer 72 and motor 73 are supported upon `abase 74. Material introduced to the mixer 72 is placed in highlyturbulent random motion and is vigorously agitated by the blades 72b.The moisture introduced through line 72e is uniformly and thoroughlymixed with the dry particles introduced through duct 83. In accordancewith the invention, the shaft 72a is rotated at a relatively rapid rateproducing a speed at the periphery of the blades `72b of about 5000-8000feet per minute. It has been discovered that this operating speed ishighly effective in producing an intimate mixture of dry high proteinparticles and moisture. There is, moreover, little tendency forundesired deposits of moist particles t-o accumulate within the mixer72. At this point in the process, the particles have not been exposed tomoisture for a sufficient period of time to produce hydration to adegree necessary to cause the particles to adhere to one another. Themoisture is, however, uniformly distributed over the surfaces of theparticles. The pitched relationship of the blades on shaft 72a willcause the particles to be advanced toward an outlet duct 75.

Material carried through duct 75 passes into a second mixer 76 which`also consists of a horizontally disposed cylinder having an axiallyextending mixer shaft 76a supported for rotation therein and driven at areduced velocity relative to mixer 72 by the provision of a suitabledrive means such as a motor 78. The mixer 76 and motor 78 are supportedupon a suitable base 77. As in the case of shaft 72a, the mixer shaft76a is provided `with a plurality of radially extending longitudinallyspaced pitched blades 76b which are oriented at an appropriate anglerelative to the shaft 76a to advance the particulate materials thereintoward the opposite end from the duct 75. The shaft 76a of the secondmixer 76 is rotated at a much slower speed to produce a peripheralvelocity on the order of from 1500-3000 feet per minute. This mixes thepreviously moistened our over therelatively long period of timenecessary to complete the thorough agglomeration of the high proteinflour particles.

The particulate material after passing through mixer 76 is exhaustedthrough duct 85 which communicates with a drying zone. The drying zonein this instance comprises a vertically disposed duct through which arising current of heated drying gas, e.g. hot air is passed. Thetemperature of the air within duct 90 can be from about 70 to 600 F. butpreferably between 200- 400 F. The air passing through duct 90 isconveniently heated by a gas heater 94 propelled by the provision of asuitable blower or fan 96 which communicates with the top of the duct 90through a collector 98 used for removing the dried agglomerates from thegas stream. The agglomerates in the collector 98 are removed through arotary discharge valve 100. Dried agglomerates are allowed to flow fromthe valve 100 through duct 102 to a sifter of a suitable conventionalknown construction 10-4 and from the sifter the coarse particles passthrough a duct 106 to a mill 108 such as a roll stand to reduce theparticles to the desired size. The particles pass out of the roll standthrough a duct 110 to a second sifter 112 similar to 104 which containsstacked screens with openings of graded sizes. In this instance, thecoarse particles are returned through a line 114 to the mill 108, thefines are returned through a line 116 to the feed hopper 67. Thefinished product which consists of agglomerates of a desired size isconveyed through a duct 118 to a finished product storage container 120.The lines from the sifter 104 are co-nducted through a conduit 105 tothe hopper 67. The finished product passing through the sifter 104 flowsthrough a duct 107 to the product storage container 120.

The apparatus described in connection with FIGURES 8-10 is capable ofoperating for substantially longer periods of time without shutdown andwithout the formation of undesired deposits of material than thatdescribed lin FIGURES 1-7. Moreover, the finished agglomerates havegreater strength and ow properties are better during pneumatic transportand bulk handling than in the case of material formed in connection withthe apparatus in FIGURES l-7 due to a reduction in the breakdown ofagglomerates during shipment. The two-stage mixing in accordance withthis form of the invention combines the dependability of a high-speedmixer 72 in producing uniform distribution of the moisture with therelatively long retention time of the mixer 76 required for successful-agglomeration of high protein ours of the type involved. Theagglomerates produced are less subject to physical breakdown than theseproduced in the apparatus of FIGURES 1-7. Both the initial ow propertiesas well as the ow properties after bulk handling are greatly improved.Standard Farinograph tests indicate a substantially improved rate ofhydration for this product as compared with either unagglomerated highprotein flour or the flour agglomerated in the apparatus of FIGURES 1-7.Bake tests indicate that it performs equal to the tlour agglomerated asin FIGURES l-7 and slightly better than unagglomerated flour. Theinvention will be better understood by reference to the followingexamples.

EXAMPLE I A high protein flour (20% protein) having a Fisher value ofabout 4 was agglomerated in an apparatus similar to that described inFIGURES 8-10. The mixer 72 had a diameter of 8 inches and a length of 30inches. The mixer 76 had a diameter of 10 inches and a length of 14inches. The speed of the periphery of blades 72b was 6250 feet perminute (2990 r.p.m.). The mixer 76 was operated to provide a peripheralspeed of 1730 feet per minute at the periphery of blades 76b (660r.p.m.). High protein flour of the type described was fed to the duct 90at the rate of 10 pounds per minute. Water was Agglomeration was carriedout as in Example I except that the S-inch mixer was operated at 5000f.p.rn. The air duct 90 was at a temperature of 325 F. The agglomerateswere similar to those described in Example I except that the moisturecontent was 14.8% by weight.

Flowability was 8.95 seconds.

EXAMPLE III Another run was conducted with the same conditions as inExample I except that the 8 inch mixer was operated at 7500 fpm. Thefinished product was the same as that described except that thefiowability was 5.1 seconds. Before being agglomated, the our had aflowabilty rate of 68.4 seconds. Bake results were equal or better thanthose of the flour in all of the Examples I-III.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made 13 Without departing from thespirit and `scope thereof, T-he specific embodiments described are givenby way of example only and the invention is limited only by the terms ofthe appended claims.

I claim:

1. A process for agglomerating a high-protein cereal grain flourfraction containing at least 18% protein and having a Fisher value ofabout 4.01, said process comprising introducing moisture to the flour toincrease the moisture content at least by Weight, briefly and thoroughlymixing the our and water by `subjecting the flour and water to agitationto bring the wetted particles into random contact with each other withina first mixing zone, immediately transferring the flour in the iirstzone directly to at least one subsequent mixing zone, subjecting theiiour that has been moistened in the first mixing zone to continuedagitation in at least one of the subsequent mixing zones for anadditional period of time such that the total mixing time is suiiicientto permit bonding together of the flour particles and thereafter -dryingthe agglomerates thus formed to rigidity the bonds between adjacentparticles.

Z. The process according to claim 1 wherein the particles are dried bytransferring the particles from the subsequent mixing zone into arelatively dry gaseous drying medium.

3. The process according to claim 1 wherein the drying medium comprisesheated air.

4. The process according to claim 3 wherein the heated air comprises astream of heated air and said agglomerates are suspended in the streamof air carried with the air stream.

5. The process according to claim 1 wherein the moisture content of theflour particles is increased to a value above about 30% by weight.

6. T-he process according to claim 1 wherein the agglomerates are driedby suspending them in an air stream maintained at a temperature betweenabout 70-600 F.

7. The process according to claim 1 wherein the moisture content of theflour particles is initially raised to a value of at least about 30% byweight, the particles are intensely agitated in the rst mixing zone fora relatively brief period of time to distribute the moisture among theparticles and holding the second mixing zone for a relatively longerperiod of time to allow hydration of the previously wetted particlessuiiicient'to promote bonding between the particles, Isaid particlesbeing thereafter transferred into a rising column of heated air fordrying the particles to rigidity the bonds therebetween.

8. The process according to claim 1 wherein said mixing zones compriseadjacent obliquely rel-ated sections of a cylinder having a zigzagshape, said cylinder being rotated about an eccentric axis positioned ina horizontal plane to shift the particles from one zone to another asthe cylinder rotates.

9. The process according to claim 1 wherein highly turbulent mixingconditions are provided in each of the mixing zones to create anintensely agitated condition, the particles being thereby present as -asuspension in a mixture of gas and moisture within the mixing zone, saidparticles being thereafter transferred from the second mixing zone to `adrying zone.

10. The product prepared in accordance with the process set forth inclaim 1.

References Cited UNITED STATES PATENTS 2,900,256 8/1959 Scott 99-562,921,857 1/1960 Sharp et al. 99-56 3,248,228 4/1966 GidloW et al.99--93 3,221,338 11/1965 Segal 99-93 3,279,924 10/ 1966 Peebles 99-93FOREIGN PATENTS 236,311 ll/ 1961 Australia.

MAURICE W. GREENSTEIN, Primary Examiner.

